// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.

#include "toft/base/arena.h"

#include "toft/base/random.h"

#include "thirdparty/gtest/gtest.h"

namespace toft {

TEST(ArenaTest, Empty) {
    Arena arena;
}

TEST(ArenaTest, Simple) {
    std::vector<std::pair<size_t, char*> > allocated;
    Arena arena;
    const int N = 100000;
    size_t bytes = 0;
    Random rnd(301);
    for (int i = 0; i < N; i++) {
        size_t s;
        if (i % (N / 10) == 0) {
            s = i;
        } else {
            s = rnd.OneIn(4000) ?
                            rnd.Uniform(6000) :
                            (rnd.OneIn(10) ? rnd.Uniform(100) : rnd.Uniform(20));
        }
        if (s == 0) {
            // Our arena disallows size 0 allocations.
            s = 1;
        }
        char* r;
        if (rnd.OneIn(10)) {
            r = arena.AllocateAligned(s);
        } else {
            r = arena.Allocate(s);
        }

        for (size_t b = 0; b < s; b++) {
            // Fill the "i"th allocation with a known bit pattern
            r[b] = i % 256;
        }
        bytes += s;
        allocated.push_back(std::make_pair(s, r));
        ASSERT_GE(arena.MemoryUsage(), bytes);
        if (i > N / 10) {
            ASSERT_LE(arena.MemoryUsage(), bytes * 1.10);
        }
    }
    for (size_t i = 0; i < allocated.size(); i++) {
        size_t num_bytes = allocated[i].first;
        const char* p = allocated[i].second;
        for (size_t b = 0; b < num_bytes; b++) {
            // Check the "i"th allocation for the known bit pattern
            ASSERT_EQ(static_cast<int>(p[b]) & 0xff, static_cast<int>(i % 256));
        }
    }
}

}  // namespace toft
